Muon Spin Rotation/Relaxation Measurements of the Noncentrosymmetric Superconductor Mg10Ir19B16

We have searched for time-reversal symmetry breaking fields in the non-centrosymmetric superconductor Mg10Ir19B16 via muon spin relaxation in zero applied field, and we measured the temperature dependence of the superfluid density by muon spin rotation in transverse field to investigate the superconducting pairing symmetry in two polycrystalline samples of signficantly different purities. In the high purity sample, we detected no time-reversal symmetry breaking fields greater than 0.05 G. The superfluid density was also found to be exponentially-flat as T-0, and so can be fit to a single-gap BCS model. In contrast, the lower purity sample showed an increase in the zero-field µSR relaxation rate below Tc corresponding to a characteristic field strength of 0.6 G. While the temperature-dependence of the superfluid density was also found to be consistent with a single-gap BCS model, the magnitude as T-0 was found to be much lower for a given applied field than in the case of the high purity sample. These findings suggest that the dominant pairing symmetry in high quality Mg10Ir19B16 samples corresponds to the spin-singlet channel, while sample quality drastically affects the superconducting properties of this system.

ACZEL A.A.;  WILLIAMS Tim;  GOKO T.;  CARLO J.P.;  YU W.;  UEMURA Y.J.;  KLIMCZUK Tomasz;  THOMPSON J. D.;  CAVA R. J.;  LUKE G.M.; 

2010-07-29

AMER PHYSICAL SOC

JRC58755

1098-0121,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC58755,   

10.1103/PhysRevB.82.024520,